可能大家有个疑问，为什么我这里不像很多网上的文章里是在apply-log后，使用copy-back如果使用/usr/bin/innobackupex --copy-back命令后，会报Original data directory is not empty! at /usr/local/xtrabackup/bin/innobackupex line 538.恢复的目录必须为空。经查官网，这是xtrabackup的一个BUG。
innobackupex–copy-back was run. With this bug fix, innobackupex–copy-back operation if the destination is not empty, avoiding potential data loss or a strang combination of a restored backup and previous data.
Bug Fixed: #737569 (Valentine Gostev) will now error out of the did not check that MySQL datadir was empty before